Hearing protectors of the type mentioned way of introduction are previously known in the art in a multiplicity of different variations and are employed in noisy environments in order to protect the hearing of the user. The hearing protector is as a rule provided with a passive noise absorbent inside the muffs which are included in the hearing protector. The volume of the muffs and the nature of the noise absorbent may be adapted in response to the nature of the noise from which the user is to be protected.
The loudspeakers disposed in the hearing protectors may be a part of a communications system, may be connected to an installation for music reproduction, but may also be connected to a microphone located outside the hearing protectors in order to convey to the user ambient sound such as speech, and instructions from a person in the proximity, or also warning signals.
As regards oral comprehension, the prior art hearing protectors of this type are often fully sufficient, since the frequency path within that range which encompasses the majority of human speech is sufficiently good.
The loudspeaker element that is traditionally employed in these practical applications may have a diameter of the order of magnitude of 20 to 30 mm. In order to avoid acoustic shorting of the loudspeaker element, it is necessary to enclose the rear side of the loudspeaker element in a capsule which prevents pressure equalisation between both sides of the membrane. However, the volume in this capsule is so slight that the frequency path, or sound pressure curve, in the base range, i.e. frequencies of below approx. 300H, is negatively affected. In listening to music, this is a major shortcoming, which is particularly manifest when listening to popular music, since a base lift is often desirable in such circumstances.